Composite current collector for zinc secondary battery and manufacturing method thereof, negative electrode sheet, zinc secondary battery

Abstract

The present application belongs to the technical field of secondary batteries, and specifically relates to a composite current collector for zinc secondary batteries and its manufacturing method, as well as a negative electrode sheet and a zinc secondary battery. The composite current collector for zinc secondary batteries according to the present application includes a substrate, a conductive layer disposed on the substrate, two metal layers, and a carbon cloth layer interposed between the two metal layers, the metal layer includes a zinc net, the mesh of the zinc net or the carbon cloth is filled with tin, and the conductive layer contains a conductive polymer and a conductive carbon material. The composite current collector for zinc secondary batteries according to the present application is manufactured by combining the zinc net and tin to manufacture a metal layer, and the carbon cloth is interposed between the metal layers, thereby ensuring the conductivity of the current collector and fundamentally reducing the corrosion of the zinc negative electrode during the use of the battery, and greatly improving the cycle performance of the battery.

Description

[Technical Field]

[0001] The present invention relates to the technical field of secondary batteries, and more particularly to a composite current collector for zinc secondary batteries and a method for producing the same, as well as a negative electrode sheet and a zinc secondary battery. [Background technology]

[0002] Zinc is an excellent battery anode material, with a high earth content, low cost, non-toxicity, and environmental friendliness, making it a promising material for many types of batteries. Zinc or zinc compounds are used as electrode materials in both primary and secondary batteries. Secondary batteries, such as nickel-zinc batteries and zinc-manganese batteries, which use zinc anodes, are characterized by high power density and high rate performance.

[0003] However, zinc secondary batteries have significant drawbacks and are not yet widely used in the industrial market. The main drawback is poor cycle performance. During battery cycling, zinc dendrites grow on the surface of the zinc negative electrode and penetrate the separator, causing a short circuit in the battery, degrading battery performance and severely impacting its cycle life. Furthermore, dissolution and deformation of the zinc negative electrode can occur, making it impossible to guarantee charge / discharge performance.

[0004] To solve these problems of zinc negative electrodes, it is common to improve the active material of the zinc negative electrode or the separator to improve the cycle performance of the battery, but the effects of these measures are very limited. Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a composite current collector for a zinc secondary battery, a manufacturing method thereof, a negative electrode sheet, and a zinc secondary battery, thereby improving the cycle performance of the zinc secondary battery. [Means for solving the problem]

[0006] To achieve the above objectives, the present invention uses the following technical solutions:

[0007] The composite current collector for a zinc secondary battery includes a substrate, a conductive layer disposed on the substrate, two metal layers, and a carbon cloth layer interposed between the two metal layers, the metal layer including a zinc mesh, and the mesh of the zinc mesh and / or the carbon cloth is filled with tin, and the conductive layer includes a conductive polymer and a conductive carbon material.

[0008] Furthermore, the conductive polymer is one of polyaniline, polypyrrole, and polythiophene.

[0009] The method for producing the composite current collector for a zinc secondary battery includes: Step 1) of interposing one layer of carbon cloth between two layers of zinc mesh, and then hot pressing the two layers of zinc mesh with the carbon cloth interposed therebetween, followed by roll pressing at a reduction rate of 10 to 50% to obtain a pressed zinc mesh; Step 2) immersing the pressed zinc mesh in the graphene dispersion, removing it, and drying it; and step 3) applying a conductive slurry containing a conductive polymer to two surfaces of the pressed zinc mesh dried in step 2) and drying the slurry.

[0010] Furthermore, in step 1), the zinc mesh is a composite zinc mesh, which is produced by filling the mesh of the zinc mesh with tin powder, and then incubating the zinc mesh filled with tin powder at 250 to 400°C for 20 to 50 minutes in an inert atmosphere.

[0011] Furthermore, the mesh size of the zinc mesh is 0.5 to 3 mm, and the particle size of the tin powder is 100 to 200 mesh.

[0012] Furthermore, in step 1), the carbon cloth is a composite carbon cloth, which is obtained by filling tin powder into the voids of the carbon cloth.

[0013] Furthermore, in step 1), the pressure of the hot press is 1 to 10 MPa, and the temperature during the hot press is 60 to 120°C.

[0014] Furthermore, in step 2), the immersion time is 2 to 8 hours.

[0015] Furthermore, in step 2), the mass fraction of graphene in the graphene dispersion is 0.1 to 15%.

[0016] Furthermore, in step 3), the conductive slurry is obtained by uniformly mixing water with a conductive polymer, a conductive carbon material, and a binder in a mass ratio of 0.5-20:0.5-10:0.1-5.

[0017] Furthermore, the conductive carbon material is one of Ketjen black and acetylene black.

[0018] The negative electrode sheet for a zinc secondary battery includes a current collector and a negative electrode material layer disposed on the surface of the current collector, and the current collector is the above-mentioned composite current collector for a zinc secondary battery.

[0019] Furthermore, the negative electrode material layer contains a negative electrode active material and a binder, and the negative electrode active material is at least one of zinc oxide, zinc, and calcium zincate.

[0020] The zinc secondary battery is characterized in that it includes a case, a positive electrode sheet, a negative electrode sheet, and an electrolyte placed in the case, and the negative electrode sheet is a negative electrode sheet for the zinc secondary battery.

[0021] Furthermore, the zinc secondary battery is one of a nickel-zinc secondary battery and a zinc-manganese secondary battery. [Effects of the Invention]

[0022] The composite current collector for zinc secondary batteries according to the present invention is made by combining zinc mesh and tin to form a metal layer, and by interposing carbon cloth between the metal layers, the conductivity of the current collector is ensured, and corrosion of the zinc negative electrode during battery use is fundamentally reduced, thereby significantly improving the cycle performance of the battery. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a comparison diagram of cycle curves of zinc secondary batteries manufactured in Example 3 and Comparative Example 1. [Figure 2] FIG. 1 is a long cycle curve diagram of the zinc secondary battery produced in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0024] The zinc secondary battery according to the present invention is either a nickel-zinc secondary battery or a zinc-manganese secondary battery. Any secondary battery using a zinc negative electrode sheet as the negative electrode can be used. The zinc negative electrode sheet here is a negative electrode sheet containing at least one of zinc oxide, zinc, and calcium zincate as the negative electrode active material.

[0025] The composite current collector for a zinc secondary battery according to the present application comprises a substrate, a conductive layer disposed on the substrate, two metal layers, and a carbon cloth layer interposed between the two metal layers, the metal layer comprising a zinc mesh, the mesh of the zinc mesh and / or the carbon cloth being filled with tin, and the conductive layer comprising a conductive polymer and a conductive carbon material.

[0026] The tin in the mesh of the zinc mesh here is metallic tin, and the metallic tin and the zinc mesh are fixed together, the fixing here being similar to welding or melting. The mesh opening of the zinc mesh is 0.5 to 3 mm. The conductive polymer is one of polyaniline, polypyrrole, and polythiophene. The conductive carbon material is one of ketjen black and acetylene black. Filling the mesh of the carbon cloth with tin means filling the voids in the carbon cloth with tin powder.

[0027] The method for producing a composite current collector for a zinc secondary battery according to the present application includes: Step 1) of interposing one layer of carbon cloth between two layers of composite zinc mesh, and then hot pressing the two layers of zinc mesh with the carbon cloth interposed therebetween, followed by roll pressing at a reduction rate of 10 to 50% to obtain a pressed zinc mesh; Step 2) immersing the pressed zinc mesh in the graphene dispersion, removing it, and drying it; and step 3) applying a conductive slurry containing a conductive polymer to two surfaces of the pressed zinc mesh dried in step 2) and drying the slurry.

[0028] In step 1), the zinc mesh is a composite zinc mesh, which is produced by filling the mesh of the zinc mesh with tin powder, and then keeping the tin powder-filled zinc mesh at 250 to 400°C for 20 to 50 minutes in an inert atmosphere.

[0029] In step 1), when filling the zinc mesh with tin powder, a polymer film is adhered to one surface of the zinc mesh, and then the zinc mesh is placed flat with the surface with the polymer film facing downwards and the other surface facing upwards. Then, tin powder is sprinkled on the zinc mesh and rubbed off.

[0030] The zinc mesh is a wire mesh or a punched zinc mesh. The mesh size of the zinc mesh is 0.5 to 3 mm. The particle size of the tin powder is 100 to 200 mesh. The polymer film is a polyethylene film or a polypropylene film.

[0031] In step 1), the inert atmosphere is nitrogen or argon. After maintaining the temperature at 250 to 400° C. for 20 to 50 minutes in the inert atmosphere, the mixture is naturally cooled to room temperature in the inert atmosphere.

[0032] In step 1), the pressure of the hot press is 1 to 10 MPa, preferably 2 to 5 MPa. The temperature during hot pressing is 60 to 120° C., preferably 80 to 100° C. The reduction ratio includes deformation by hot pressing and roll pressing. In step 2), the immersion time is 2 to 8 hours, preferably 2 to 5 hours. The mass fraction of graphene in the graphene dispersion is 0.1 to 15%. Furthermore, the mass fraction of graphene is 1 to 10%. After the immersion, the pressed zinc mesh is removed and then vacuum dried. The vacuum drying temperature is 40 to 100°C.

[0033] In step 3), the conductive polymer is one of polyaniline, polypyrrole, and polythiophene. The conductive slurry further contains a conductive carbon material. The conductive carbon material is one of ketjen black and acetylene black.

[0034] Furthermore, the conductive slurry is obtained by uniformly mixing water with a conductive polymer, a conductive carbon material, and a binder in a mass ratio of 0.5-20:0.5-10:0.1-5. Preferably, the conductive slurry is obtained by uniformly mixing water with a conductive polymer, a conductive carbon material, and a binder in a mass ratio of 1-8:0.5-5:2-3.

[0035] The binder is at least one of polytetrafluoroethylene, polyvinylidene fluoride, carboxymethyl cellulose, and styrene-butadiene rubber latex. The conductive slurry is applied to two surfaces of the pressed zinc mesh, which is then vacuum dried. The vacuum drying temperature is 60 to 80°C. The drying time is 2 to 8 hours.

[0036] The negative electrode sheet for a zinc secondary battery according to the present application includes a current collector and a negative electrode material layer disposed on the surface of the current collector, and the current collector is the composite current collector for a zinc secondary battery.

[0037] The negative electrode layer contains a negative electrode active material and a binder. The negative electrode active material is at least one of zinc oxide, zinc, and calcium zincate. The negative electrode layer further contains zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, and sodium dihydrogen phosphate in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1.

[0038] The zinc secondary battery according to the present application includes a case, and a positive electrode sheet, a negative electrode sheet, and an electrolyte solution placed in the case, and the negative electrode sheet is the negative electrode sheet for the zinc secondary battery.

[0039] Example 1 The method for producing a composite current collector for a zinc secondary battery according to this embodiment is as follows: A polymer film, which is a polyethylene film, is adhered to one surface of the zinc mesh, and then the zinc mesh is placed flat so that the surface with the polymer film attached faces downward and the other surface faces upward. Next, tin powder with a particle size of 100 mesh is sprinkled onto the zinc mesh with a mesh opening of 1 mm, the surface of the zinc mesh is scraped off, and one layer of polymer film is adhered to the top surface of the zinc mesh. Step 1) of keeping the treated zinc mesh at 350°C for 30 minutes under the protection of an inert atmosphere, and then naturally cooling it to room temperature under an inert atmosphere to obtain a composite zinc mesh; The composite zinc mesh was folded in half, and a carbon cloth was interposed between the two. The size of the carbon cloth was made slightly larger than half of the zinc mesh so that a portion of the carbon cloth was exposed to the zinc mesh with the carbon cloth interposed. Then, the zinc mesh with the carbon cloth interposed was hot pressed at a pressure of 2 MPa and a temperature of 80°C. Next, the hot-pressed zinc mesh is roll-pressed by a roll press machine, and the roll press is stopped until the reduction rate of the zinc mesh is about 30%, thereby obtaining a pressed zinc mesh. Step 3) immersing the pressed zinc mesh in a graphene dispersion obtained by uniformly dispersing graphene and water in a mass ratio of 5:95 for 2 hours, removing the immersed pressed zinc mesh, and drying it in a vacuum at 40°C; and step 4) uniformly mixing polyaniline, Ketjen black, carboxymethyl cellulose, and water in a mass ratio of 8:5:3:84 to obtain a conductive slurry, which is then applied to two surfaces of a pressed zinc mesh and vacuum-dried at 60°C for 3 hours to obtain a composite current collector.

[0040] The negative electrode sheet for a zinc secondary battery according to this embodiment includes a current collector and a negative electrode material layer disposed on the surface of the current collector, the current collector being the composite current collector for a zinc secondary battery described above, and the negative electrode material layer is formed by applying a negative electrode slurry to the current collector and drying it. The negative electrode slurry is obtained by uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5.

[0041] The method for producing a negative electrode sheet for a zinc secondary battery according to this embodiment is as follows: Step S1: uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5 to obtain a conductive slurry; and step S2 of applying a negative electrode slurry to two surfaces of the composite current collector for a zinc secondary battery, drying, roll pressing, and cutting to obtain a negative electrode sheet for a zinc secondary battery.

[0042] The zinc secondary battery of this embodiment is a nickel-zinc battery, and includes a cylindrical steel case (AAA). A cell and an electrolyte are placed inside the steel case. The cell is manufactured by sequentially stacking a positive electrode sheet, a separator, a negative electrode sheet, and a separator, and then winding them. The negative electrode sheet is the above-mentioned negative electrode sheet, the positive electrode sheet includes a positive electrode current collector, and the positive electrode current collector is nickel tape. Positive electrode material layers are applied and placed on two surfaces of the positive electrode current collector. The positive electrode material layer contains a positive electrode active material, a binder, etc., and the positive electrode active material is nickel hydroxide.

[0043] Example 2 The method for producing a composite current collector for a zinc secondary battery according to this embodiment is as follows: A polymer film, which is a polyethylene film, is adhered to one surface of the zinc mesh, and then the zinc mesh is placed flat with the surface with the polymer film facing downward and the other surface facing upward. Next, a small amount of polyethylene powder (D50 is about 150 μm) is sprinkled on the zinc mesh, and the polyethylene powder is scraped down into the mesh of the zinc mesh with a scraper. The amount of polyethylene powder is determined so that the height of the polyethylene powder in the mesh is about one-third the thickness of the zinc mesh. Next, tin powder with a particle size of 100 mesh is sprinkled on a zinc mesh with a mesh opening of 1 mm, and the surface of the zinc mesh is scraped down, and one layer of polymer film is adhered to the top surface of the zinc mesh. Step 1) after the above treatment, the zinc mesh is kept at 400 ° C for 22 minutes under the protection of an inert atmosphere, and then cooled naturally to room temperature under an inert atmosphere to obtain a composite zinc mesh, and when kept at 400 ° C, the surface sprinkled with polyethylene powder faces upward; The composite zinc mesh was folded in half, and a carbon cloth was interposed between the two. The size of the carbon cloth was made slightly larger than half of the zinc mesh so that a portion of the carbon cloth was exposed to the zinc mesh with the carbon cloth interposed. Then, the zinc mesh with the carbon cloth interposed was hot pressed at a pressure of 5 MPa and a temperature of 100°C. Next, the hot-pressed zinc mesh is roll-pressed by a roll press machine, and the roll press is stopped until the reduction rate of the zinc mesh is about 26%, thereby obtaining a pressed zinc mesh. Step 3) immersing the pressed zinc mesh in a graphene dispersion obtained by uniformly dispersing graphene and water in a mass ratio of 10:90 for 6 hours, removing the immersed pressed zinc mesh, and drying it in a vacuum at 55°C; and step 4) uniformly mixing polyaniline, Ketjen black, carboxymethyl cellulose, and water in a mass ratio of 5:3:2:90 to obtain a conductive slurry, which is then applied to two surfaces of a pressed zinc mesh and vacuum-dried at 80°C for 2 hours to obtain a composite current collector.

[0044] The negative electrode sheet for a zinc secondary battery according to this embodiment includes a current collector and a negative electrode material layer disposed on the surface of the current collector, the current collector being the composite current collector for a zinc secondary battery described above, and the negative electrode material layer is formed by applying a negative electrode slurry to the current collector and drying it. The negative electrode slurry is obtained by uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5.

[0045] The method for producing a negative electrode sheet for a zinc secondary battery according to this embodiment is as follows: Step S1: uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5 to obtain a conductive slurry; and step S2 of applying a negative electrode slurry to two surfaces of the composite current collector for a zinc secondary battery, drying, roll pressing, and cutting to obtain a negative electrode sheet for a zinc secondary battery.

[0046] The zinc secondary battery of this embodiment is a nickel-zinc battery, and includes a cylindrical steel case (AAA). A cell and an electrolyte are placed inside the steel case. The cell is manufactured by sequentially stacking a positive electrode sheet, a separator, a negative electrode sheet, and a separator, and then winding them. The negative electrode sheet is the above-mentioned negative electrode sheet, the positive electrode sheet includes a positive electrode current collector, and the positive electrode current collector is nickel tape. Positive electrode material layers are applied and placed on two surfaces of the positive electrode current collector, and the positive electrode material layer contains a positive electrode active material, a binder, etc., and the positive electrode active material is nickel hydroxide.

[0047] Example 3 The method for producing a composite current collector for a zinc secondary battery according to this embodiment is as follows: A polymer film, which is a polyethylene film, is adhered to one surface of the zinc mesh, and then the zinc mesh is placed flat with the surface with the polymer film facing downwards and the other surface facing upwards. Next, a small amount of polyethylene powder (D50 is about 150 μm) is sprinkled on the zinc mesh, and the polyethylene powder is scraped down into the mesh of the zinc mesh with a scraper. The amount of polyethylene powder is determined so that the height of the polyethylene powder in the mesh is about one-third the thickness of the zinc mesh. Next, tin powder with a particle size of 100 mesh is sprinkled on a zinc mesh with a mesh opening of 0.8 mm, and the surface of the zinc mesh is scraped down, and one layer of polymer film is adhered to the top surface of the zinc mesh. Step 1) of keeping the treated zinc mesh at 405°C for 20 minutes under the protection of an inert atmosphere, and then naturally cooling to room temperature under an inert atmosphere to obtain a composite zinc mesh, and when keeping it at 405°C, the surface sprinkled with polyethylene powder faces upward; The composite zinc mesh is folded in half, and a carbon cloth is interposed between the two. The size of the carbon cloth is made slightly larger than half of the zinc mesh so that a portion of the carbon cloth is exposed to the zinc mesh with the carbon cloth interposed. Then, the zinc mesh with the carbon cloth interposed is hot pressed at a pressure of 3.5 MPa and a temperature of 85°C. Next, the hot-pressed zinc mesh is roll-pressed by a roll press machine, and the roll press is stopped until the reduction rate of the zinc mesh is about 30%, thereby obtaining a pressed zinc mesh. Step 3) immersing the pressed zinc mesh in a graphene dispersion obtained by uniformly dispersing graphene and water in a mass ratio of 1:99 for 5 hours, removing the immersed pressed zinc mesh, and drying it in a vacuum at 45°C; and step 4) uniformly mixing polyaniline, Ketjen black, carboxymethyl cellulose, and water in a mass ratio of 3:4.5:2.5:90 to obtain a conductive slurry, which is then applied to two surfaces of a pressed zinc mesh and vacuum-dried at 70°C for 2 hours to obtain a composite current collector.

[0048] The negative electrode sheet for a zinc secondary battery according to this embodiment includes a current collector and a negative electrode material layer disposed on the surface of the current collector, the current collector being the composite current collector for a zinc secondary battery described above, and the negative electrode material layer is formed by applying a negative electrode slurry to the current collector and drying it. The negative electrode slurry is obtained by uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5.

[0049] The method for producing a negative electrode sheet for a zinc secondary battery according to this embodiment is as follows: Step S1: uniformly mixing zinc oxide, zinc, indium tin oxide, bismuth oxide, tin oxide, polytetrafluoroethylene, sodium polyacrylate, glycerin, sodium dihydrogen phosphate, and water in a mass ratio of 63:21:0.2:2:3:5:0.25:1:1:5 to obtain a conductive slurry; and step S2 of applying a negative electrode slurry to two surfaces of the composite current collector for a zinc secondary battery, drying, roll pressing, and cutting to obtain a negative electrode sheet for a zinc secondary battery.

[0050] The zinc secondary battery of this embodiment is a nickel-zinc battery, and includes a cylindrical steel case (AA). A cell and an electrolyte are placed inside the steel case. The cell is manufactured by sequentially stacking a positive electrode sheet, a separator, a negative electrode sheet, and a separator, and then winding them. The negative electrode sheet is the above-mentioned negative electrode sheet, the positive electrode sheet includes a positive electrode current collector, and the positive electrode current collector is nickel tape. Positive electrode material layers are applied and placed on two surfaces of the positive electrode current collector, and the positive electrode material layer contains a positive electrode active material, a binder, etc., and the positive electrode active material is nickel hydroxide.

[0051] Example 4 In this example, when producing a negative electrode sheet based on the above Example 3, the obtained negative electrode sheet for a zinc secondary battery is immersed in a graphene dispersion liquid for 1 to 2 hours, then taken out and dried, and one graphene layer is deposited on the surface of the negative electrode material layer.

[0052] The zinc secondary battery according to this example is a nickel-zinc battery, and reference is made to the nickel-zinc battery according to Example 3.

[0053] Example 5 The difference between this example and Example 1 is that tin powder is not filled into the mesh of the zinc mesh, and a punched zinc mesh is directly used instead of a composite zinc mesh, and a pretreatment is carried out before using the carbon cloth. The pretreatment includes spreading the carbon cloth flat, sprinkling tin powder with a particle size of 200 mesh on its surface, and then scraping the surface of the carbon cloth back and forth with a scraper so that the tin powder fills the mesh of the carbon cloth, thereby obtaining a composite carbon cloth instead of the carbon cloth in step 2) of Example 1.

[0054] The zinc secondary battery according to this example is a nickel-zinc battery, and reference is made to the nickel-zinc battery according to Example 3.

[0055] Comparative Example 1 The difference between this comparative example and Example 1 is that the same zinc mesh as in Example 1 is used as a current collector, and the rest is the same as in Example 1.

[0056] Experimental example (1) Ten AA steel case batteries were manufactured according to Example 3 and designed to have a capacity of 1500 mAh, and electrochemical tests were carried out, and the test results are shown in the table below. [Table 1] Ten AA steel case batteries were fabricated according to Comparative Example 1, each designed to have a capacity of 1500 mAh, and electrochemically tested, with the test results shown in the table below. [Table 2] (2) An AA steel case battery was manufactured according to Example 3 and Comparative Example 1, and the capacity was designed to be 1500 mAh. Then, a cycle test was carried out, and the test results are shown in Figure 1. The long cycle curve of the battery according to Example 3 is shown in Figure 2.

Claims

1. Step 1) of interposing one layer of carbon cloth between two layers of zinc mesh, hot pressing the two layers of zinc mesh with the carbon cloth interposed therebetween, and then roll pressing at a reduction ratio of 10 to 50% to obtain a pressed zinc mesh; Step 1) wherein the zinc mesh is a composite zinc mesh and tin is filled into the mesh of the zinc mesh; 2) immersing the pressed zinc mesh in a graphene dispersion, removing the immersed pressed zinc mesh, and drying it; and step 3) applying a conductive slurry containing a conductive polymer to two surfaces of the dried pressed zinc mesh and then drying it again to obtain a composite current collector for a zinc secondary battery.

2. 2. The method for producing a composite current collector for a zinc secondary battery according to claim 1, wherein the method for producing the composite zinc mesh comprises filling tin powder into meshes of the zinc mesh, and then maintaining the tin powder-filled zinc mesh at 250 to 400°C for 20 to 50 minutes in an inert atmosphere to obtain the composite zinc mesh.

3. The method for producing a composite current collector for zinc secondary batteries according to claim 2, characterized in that the mesh opening of the zinc mesh is 0.5 to 3 mm, and the particle size of the tin powder is 100 to 200 mesh.

4. The carbon cloth is a composite carbon cloth, and the composite carbon cloth is obtained by filling tin powder into the voids of the carbon cloth.

5. 2. The method for producing a composite current collector for a zinc secondary battery according to claim 1, wherein the pressure of the hot press is 1 to 10 MPa, and the temperature when the hot press is performed is 60 to 120°C.

6. 2. The method for producing a composite current collector for a zinc secondary battery according to claim 1, wherein in step 2), the immersion time is 2 to 8 hours.

7. The method for producing a composite current collector for a zinc secondary battery according to claim 1, wherein a mass fraction of graphene in the graphene dispersion is 0.1 to 15%.

8. The method for producing a composite current collector for zinc secondary batteries according to any one of claims 1 to 7, characterized in that the conductive slurry is obtained by uniformly mixing water, the conductive polymer, the conductive carbon material, and a binder, and the mass ratio of the conductive polymer, the conductive carbon material, and the binder is 0.5 to 20:0.5 to 10:0.1 to 5.

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